Automated drill bit changer

ABSTRACT

A drill bit changer system for a drill rig including a drill bit storage holder assembly arranged to be movable mounted to the drill rig. The drill bit assembly includes a rotatable drill bit storage holder, a plurality of bit holder receptacles located within the drill bit storage holder, and a plurality of drill bit adaptor assemblies disposed in the bit holder receptacles. Each adaptor assembly includes an adaptor having opposed ends, one end of the adaptor being arranged to engage a drill string of the drill rig and another end of the adaptor being engageable with a drill bit, wherein the adaptor has a rounded section disposed between the opposed ends, the rounded section being engageable by an adaptor arm of the drill bit holder assembly to engage and disengage the drill bit adaptor assembly from the drill string. A method of changing a drill bit is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of U.S. Provisional Application No. 62/483,808, filed Apr. 1, 2015, which the entirety thereof is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an automated drill bit changing system for a mobile drill rig and a changing process.

BACKGROUND

Mobile drill rigs are commonly used in surface mining operations. Surface mining requires drilling patterns of holes to specific depths and angles into the drill bed. Self-propelled rigs preliminarily drill these holes. Later, the mine uses sequences of explosive charges to break up the bedrock (or other subsurface constituents) so that the large end loaders or drag lines can scoop up the material to transfer to dump trucks for relocation to the processing areas at the mine.

Many of the operations involved in servicing and maintaining the rigs are difficult and hazardous. Finding ways to automate these processes can, not only result in a machine that is easier to maintain, but also reduce cost and increase efficiency. One such task is replacing the rotary drill bit.

The current process for changing out bits is done manually with a mechanic and an operator. However, the leading standard today in drill rig technology is automation. Customers and suppliers would like to reduce the need for operators of the drill rig to increase safety and efficiency. Many tasks performed by the above type of drill rig have been successfully automated, however, automation of changing a drill bit has been attempted but has proven difficult to perfect.

Automating the process is needed in order to keep moving forward with the growing needs of the industry. By using the process of automation bit replacement, time can be drastically reduced and a faster, more reliable mechanism to change bits ultimately will save money. It will also improve the safety and eliminate potential bodily harm to the mechanic and/or the operator by eliminating the need for human interaction with the heavy drill bits and the confined operating environment.

One hindering factor towards automating bit changing is that rig space is limited, meaning that the machine will have to be engineered to fit on a variety of rigs without using too much space.

Another problem of automated drill bit changing is the non-uniform geometry of the drill bit itself. When the bit rotates, a different surface is presented, making it difficult to have a form fitted device to grab onto the bit. The carbide steel that the bit is made out of also causes damage to softer metals being used to grab the bit.

Thus, there is a need for an automated blast drill bit changing system that is capable of being automated, reliable, capable of being easily fitted to a blast-hole drill rig, designed to allow for easy restocking of bits, capable of storing new bits and holding the old bits after being replaced, robust, compact and able to handle extreme conditions, and safe to use.

SUMMARY

The aim of the present disclosure is to overcome or at least reduce the above-mentioned problems. Therefore, the present disclosure relates to an automated drill bit changing system including a drill bit storage holder assembly arranged to be movable mounted to the drill rig, the drill bit assembly including a rotatable drill bit storage holder; a plurality of bit holder receptacles located within the drill bit storage holder; and a plurality of drill bit adaptor assemblies disposed in the bit holder receptacles, each drill bit adaptor assembly being received within a respective bit holder receptacle, and each adaptor assembly including an adaptor having opposed ends, one end of the adaptor being arranged to engage a drill string of the drill rig and another end of the adaptor being engageable with a drill bit, wherein the adaptor has a rounded section disposed between the opposed ends, the rounded section being engageable by an adaptor arm of the drill bit holder assembly to engage and disengage the drill bit adaptor assembly from the drill string.

In another embodiment, a method of changing a drill bit of a drill rig includes the steps of providing a drill bit changing system, the drill bit changing system including a drill bit storage holder assembly arranged to be movable mounted to the drill rig, the drill bit storage assembly including a rotatable drill bit storage holder, a plurality of bit holder receptacles located within the drill bit storage holder and a plurality of drill bit adaptor assemblies disposed in the bit holder receptacles, each drill bit adaptor assembly being received within a respective bit holder receptacle, and each adaptor assembly including an adaptor having opposed ends, one end of the adaptor being arranged to engage a drill string of the drill rig and another end of the adaptor being engageable with a drill bit, wherein the adaptor has a rounded section disposed between the opposed ends, the rounded section being engageable by an adaptor arm of the drill bit holder assembly to engage and disengage the drill bit adaptor assembly from the drill string; pivoting the drill bit storage system to a first position whereby the drill bit storage holder is position to engage a drill bit adaptor assembly; removing a used drill bit and adaptor assembly from the drill string; indexing the drill bit storage holder to position a new drill bit adaptor assembly to the drill string; attaching the new drill bit adaptor assembly to the drill string; and pivoting the drill bit storage system to a second position whereby the drill bit storage system is stowed away from the drill string.

By using available technology, such as sensors, hydraulics, electromagnets, and motors, it is possible to revolutionize the process for changing mining bits.

The foregoing summary, as well as the following detailed description of the embodiments, will be better understood when read in conjunction with the appended drawings. It should be understood that the embodiments depicted are not limited to the precise arrangements and instrumentalities shown.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is schematic view of a mobile drill rig with an automated drill bit changing system according to the present disclosure.

FIG. 2 is a perspective view of the drill bit changing system.

FIG. 3 is an enlarged perspective view of the drill bit storage holder of the present disclosure.

FIG. 4 is an enlarged perspective view of the drill bit and adaptor assembly.

FIG. 5 is a schematic view of the automated control system of the present disclosure.

FIGS. 6A-6E illustrate the drill bit changing process according to the system of the present disclosure.

DETAILED DESCRIPTION

The present disclosure relates to a drill bit changing system for removing worn out bits from a drill string and replace such with new bits with limited need for physical human intervention, i.e., machine operator and/or maintenance personnel. Referring to FIG. 1, a movable blast hole rig 10 includes a mast or derrick 12. It should be appreciated that although the system of the present disclosure is described in relation to a drill rig, the same can be used on different types of apparatus. An automated drill bit changer 20, which will be described in detail below, is movably disposed on the mast.

At least one control unit 16 is arranged to control various components of the drill bit changer 20. The control unit 16 can be a computer, processing device, or any corresponding device arranged to execute a computer executable code and may include a user interface with a display device as well as control means for giving commands and information to the drill bit changer 20. Control unit 16 may be a computer equipped with appropriate software that can be accessed and controlled by the operator of the drill rig. Additionally, control unit can be operated remotely. By using sensors, hydraulics, electromagnets, and motors, it is possible to automate the process for changing mining bits.

Some details of the selected hardware of drill bit changer 20 that will perform the necessary functions are described with reference to FIGS. 2-6E. The objectives of each of the hardware components are derived from the critical sub functions that each performs, for example, holding and storing of the adaptors and an adaptor/bit assembly, as will be described further herein. Each of these subsystems has its own unique mechanisms to accomplish the objectives.

Referring to FIGS. 2 and 3, a first component of the drill bit changer 20 is a bit storage holder 22 for bits 24. The bit storage holder 22 can include a carousel 26 having a plurality of bit receptacles 28 for receiving the bits 24 and adaptor 30 that together form the drill bit adaptor assembly. It should be appreciated that although shown as a cup type receptacle, other bit holder arrangements are contemplated.

Carousel 26 is movably positioned on mast 12 via pivoting arm assemblies 32 and mast mounts 34. Each arm assembly includes a hydraulic cylinder 36 that can be controlled by control unit 16 as described further herein.

The bit storage holder 22 keeps the bit/adaptor in place so that it can be correctly positioned to be able to add/remove it to/from the drill string. It also provides storage for used and unused adaptor/bit assemblies. The bit storage holder 22 also includes a top 27, which keeps the drill bit adaptor assemblies 24, 30 in place when the mast/derrick of the rig is lowered to horizontal position and trammed. The drill bit storage holder is mounted to the arm assemblies 32 via a central shaft 33 that connects the two mounting arms.

Bit storage holder 22 is arranged to hold a plurality of bits, for example, between 3-6 bits. However, due to space constraints, the bit storage system must not have a size that would interfere with the current drill tower due to rotation of the bit holder 22. Drill bit storage holder 22 must be able to rotate and index to proper position so the drill pipe can connect with a new bit. Accordingly, the drill bit storage holder is indexed by a slew drive 38. Slew drive 38 can be a worm gear mechanism actuated by a hydraulic motor capable of provide rotational actuation. Indexing of the slew drive can be controlled by control unit 16.

As will be described further herein, the slew drive indexes the carousel from one bit cup 28 to the next to allow the drill bit adaptor assemblies 24, 30 to be accessed. An encoder 37 is mounted to central shaft 33 to monitor the position of the new/used bits so that the process is automated through control system 16.

The bit storage holder 22 must be able to support the load of all of bits and the bit adaptors. Thus, the material thereof is chosen so as to be strong enough and to prevent deflection of the bit storage that may lead to alignment issues.

Referring to FIG. 4, and as set forth above, a plurality of drill bit adaptor 30 and drill bits 24 are accommodated in drill bit storage holder 22. Adaptor 30 aides in the automation process as it is easier to remove and add the bit adaptor to the drill string than the bit. The bit adaptor 30 can be a tube having a pin thread on one end 42 to engage with the drill string under the rotary head and another having a thread on an opposed end 44 to engage with a bit 24. Typically on blast hole rigs API or beco threads are used. Additionally, the bit adaptor has a necked down, round section 46, which is engaged by adaptor arm 40 to hold the adaptor/bit assembly so that the threaded joint between the adaptor and the drill string can be broken and a new adaptor/bit assembly can be added to the drill string.

Because bits are by nature not uniformly shaped and are not easily handled with mechanisms, adaptor 30 can be more easily handled by currently used mechanisms. Additionally, drill pipes, adapters and tools have traditionally been equipped with flats cut into the wall to hold and arrest the rotation and enable the breaking of the threaded joints between parts to add/remove pieces. However, these flats can be difficult to adapt to automation as they have to be aligned. The round interface of adaptor 30 at section 46 can be more easily automated.

FIG. 5 illustrates the automated control system including control unit 16. As shown, control unit 16 communicates with slew drive 38, hydraulic arm assemblies 32 and encoder 37. As set forth supra, the drill bit storage holder 22 is indexed by slew drive 38 to provide rotational actuation. Indexing of the slew drive can be controlled by control unit 16. Each of the arm assembly hydraulic cylinders 36 can also be controlled by control unit 16 to pivot the holder 22 into and out of position. Moreover, encoder 37 is mounted to central shaft 33 to monitor the position of the bits to enable automated control by unit 16. As discussed supra, a consideration in undertaking automate drill bit changing is cross threading the drill bit. Cross threading the bit reduces the reliability of the entire system because to de-thread the connection now requires operator interaction. To avoid cross threading this system will be automated to be within alignment tolerances via use of the slew drive and encoder

FIGS. 6A-6E e illustrate the drill bit changing process. In the first step shown in FIG. 6A, drill pipe finishes drilling and raises up. In step 2, FIG. 6B, drill bit storage holder 22 is rotated to meet the pipe and empty arm 40 engages the rounded section of adaptor 30, the bit adaptor being previously broken loose from the bit sub by a deck wrench (not shown) as the bit storage holder moves into place. With the top 36 removed for illustration, next as shown in FIG. 6C, the uses bit and adaptor assembly held by arm 40 is unscrewed by manipulating the drill rigs feeding and rotation system. Next as shown in FIG. 6D, drill bit storage holder 22 is controlled to be indexed by slew drive 38 to position a new bit and adaptor to the pipe and the same is screwed onto the drill pipe as disclosed above, but in an opposite direction of rotation of the rig feeding and rotation system. In the last step, FIG. 6E, the assembly swings back out of the way and drilling commences.

As set forth supra, the mounting arms are mounted to the mast/derrick via mast mounts and actuated by hydraulic cylinders. The actuated cylinders move the holding/storage mechanism from a stowed position (FIG. 6a ) to an engaged swung in position (FIG. 6B) for a new/used adaptor bit assembly to be added/removed. It should be appreciated that the drill bit storage holder mechanism must be able to move out of the way during regular drilling operations. It moves out of the way via the same hydraulic cylinders that swing the holding/storage mechanism into position to add/remove the adaptor/bit sub. The system is also responsible for moving the bit storage into the proper position so that it can then index to its proper position. The carousel 26 holds all of the individual bits for storage. The carousel is able to rotate due to the slew drive shown underneath the bit storage area.

The present drill bit changing system externally interacts with the operator, the environment and the drill rig itself. A robust, weatherproof design is required to withstand environmental abuse. The drill rig will be applying numerous forces to the bit changing system, so a robust attachment at the joint will be required.

The drill rigs operate in very harsh environments. The rigs are designed to withstand extreme temperatures, rain and snow and debris damage. The drill bit changing system proposed here will need to withstand these same conditions. These conditions can damage and ultimately reduce the life of the drill bit changing system.

For the drill bit changer to operate reliably it will need to be constructed similar to the existing components of the drill rig system. The system which the drill bit changer was modeled after was the drill pipe changer. The drill pipe changing system uses a robust hydraulically powered system to add or subtract length to the in service drill pipe. The drill bit changing system will be similarly robust.

There are also quality and reliability objectives for the system. The system must be structurally sufficient while holding multiple bits. Further, these bits must have a guaranteed alignment and position to ensure system reliability.

The drill bit changing system will be able to withstand all of the incident stresses while in standby and drilling operation. These stresses can range from those caused by the weight of the bit to those caused by vibration during drilling.

Alignment is another consideration. To ensure reliability, the drill bit needs to be in a guaranteed position to avoid cross threading a bit to the drill pipe. A cross thread will cause an equipment shutdown because of an inability to remove the drill bit. To ensure alignment, the system is constructed similar to the drill pipe exchanger, which uses position control via, for example, a slew drive.

The purpose of automating a system or process is to allow that process to run without any human interaction. To ensure a maximum of automation and a minimum of human interaction the changing system will need to house as many unused drill bits as possible.

Blast hole drill rigs operate in some very remote areas of the planet. These areas often times come with extreme conditions including blizzards, earthquakes and hurricanes. Environmental conditions are worsened when dirt, dust and rock begin to be kicked up and thrown around during drilling operation. To withstand these conditions, the system is structurally robust. As mentioned above, the system is designed based on existing drill rig components' structural robustness to compensate for dangerous conditions.

Although the present embodiment(s) has been described in relation to particular aspects thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred therefore, that the present embodiment(s) be limited not by the specific disclosure herein, but only by the appended claims. 

What is claimed is:
 1. A drill bit changer system for a drill rig, the system comprising: a drill bit storage holder assembly arranged to be movably mounted to the drill rig, the drill bit assembly including a rotatable drill bit storage holder; a plurality of bit holder receptacles located within the drill bit storage holder; and a plurality of drill bit adaptor assemblies disposed in the bit holder receptacles, each drill bit adaptor assembly being received within a respective bit holder receptacle, and each adaptor assembly including an adaptor having opposed ends, one end of the adaptor being arranged to engage a drill string of the drill rig and another end of the adaptor being engageable with a drill bit, wherein the adaptor has a rounded section disposed between the opposed ends, the rounded section being engageable by an adaptor arm of the drill bit holder assembly to engage and disengage the drill bit adaptor assembly from the drill string.
 2. The drill bit changer system of claim 1, wherein the drill bit storage holder is a rotatable carousel that is indexable to position a respective drill bit adaptor assembly or an empty bit holder receptacle to the drill string.
 3. The drill bit changer assembly of claim 1, wherein the drill bit storage holder is indexable by a slew drive.
 4. The drill bit changer system of claim 1, wherein the drill bit storage holder is pivotally connected to a mast of the drill rig to move the drill bit storage holder between a stowed position to an engaged position for a new or used adaptor bit assembly to be added or removed from the drill string.
 5. The drill bit changer system of claim 5, wherein the drill bit storage holder is pivotally connected to the drill mast by at least one hydraulically operated arm.
 6. The drill bit changer system of claim 1, further comprising at least one processing device arranged to execute a computer executable code to control the pivotable and rotatable movement of the drill bit storage holder.
 7. A method of changing a drill bit of a drill rig comprising the steps of: providing a drill bit changer system, the drill bit changer system including a drill bit storage holder assembly arranged to be movable mounted to the drill rig, the drill bit storage assembly including a rotatable drill bit storage holder, a plurality of bit holder receptacles located within the drill bit storage holder and a plurality of drill bit adaptor assemblies disposed in the bit holder receptacles, each drill bit adaptor assembly being received within a respective bit holder receptacle, and each adaptor assembly including an adaptor having opposed ends, one end of the adaptor being arranged to engage a drill string of the drill rig and another end of the adaptor being engageable with a drill bit, wherein the adaptor has a rounded section disposed between the opposed ends, the rounded section being engageable by an adaptor arm of the drill bit holder assembly to engage and disengage the drill bit adaptor assembly from the drill string; pivoting the drill bit storage system to a first position whereby the drill bit storage holder is positioned to engage a drill bit adaptor assembly; removing a used drill bit and adaptor assembly from the drill string; indexing the drill bit storage holder to position a new drill bit adaptor assembly to the drill string; attaching the new drill bit adaptor assembly to the drill string; and pivoting the drill bit storage system to a second position whereby the drill bit storage system is stowed away from the drill string.
 8. The method of claim 7, wherein the piviotal movement of the drill bit storage system and the indexing of the drill bit storage holder is controlled by a computerized control unit executing a computer executable code. 